Dotted Slug - Arion circumscriptus


    Usually 30-40 mm. This slug belongs to a species complex (Arion fasciatus group) containing the following species: Arion silvaticus, A. circumscriptus and A. fasciatus which are hard to distinguish without dissecting the genitalia, though some visual differences are present - see below. All are greyish centrally and white laterally with a pair of dark-colored longitudinal stripes.However Arion circumscriptus has speckly markings on the mantle and the tentacles and head are black in colour. The pneumostome (breathing pore) occurs in the anterior one-third of the slug's mantle on the right side of the body. In contracted individuals the body is bell-shaped. No keel is present in this group; however, an enlarged row of pale coloured tubercles may create an impression that one may exist (false keel). The sole of this species-complex is pale coloured, similar to the foot fringe and the mucus secreted by this group is colourless or occasionally pale yellow.

    Similar Species

    Arion circumscriptus - speckles on the mantle + grey flanks below the stripe

    Arion silvaticus - pale silver flanks below the stripe

    Arion fasciatus - yellow flanks below the stripe

    Identification difficulty

    A wide range of habitats, and will tolerate damper conditions than some other species.

    When to see it

    All year.

    UK Status

    Common though under-recorded due to the similarity with other Arion species.

    VC55 Status

    Fairly common in Leicestershire and Rutland.

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    Leicestershire & Rutland Map

    MAP KEY:

    Yellow squares = NBN records (all known data)
    Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

    UK Map